This article was published in ‘DSTO Connections’ in August 2012 and has been reproduced here with permission. The Defence Science and Technology Organisation (DTSO) is part of Australia’s Department of Defence.
Ben Withy from New Zealand’s Defence Technology Agency (DTA) has teamed up with DSTO scientists to conduct failure analysis of composite materials in a win-win for both organisations.
For some time Stephan Toman (AVD) [Air Vehicles Division] has been compiling a handbook for composite material failure analysis, a task that arose from TTCP [The Technical Cooperation Program] Materials Technical Panel 7.
National Panel Leaders Paul Callus (AVD) and Ryan Brookes (DTA) arranged for Ben to spend two six-week periods in AVD’s Aircraft Materials Branch contributing to the handbook work. Along the way Ben would build up a skill set in composite material failure analysis that would be useful for the NZDF [New Zealand Defence Force] which has recently acquired a fleet of carbon fibre NH-90 helicopters (similar to the ADF’s [Australian Defence Force’] MRH-90 helicopter).
Composite science investigations
“It’s been incredibly useful,” says Ben. “I’ve been essentially working as if I’d been doing various small failure investigations into broken components; some lab-generated and some actual ADF and NZDF composite failures. Just having the equipment available and the expertise here… whenever I get to a point where it makes no sense I’ve been able to ask for advice.” Ben examined a failed adhesive bond in a rigid hull inflatable for the Royal NZ Navy, and part of a failed rotor blade from a helicopter.
“I’ve been essentially familiarising myself with a whole lot of different failure surfaces and what they look like after different compression, bending and impact failures. And understanding the loading sequence that relates to what you see in the visual, macroscopic and microscopic scales using different imaging techniques.”
New skill set
Ben says the DTA expects to be asked for advice in the future about the carbon fibre helicopters. “We’ll be asked ‘What’s this damage?’ and ‘What caused the damage?’ And before this venture we didn’t have a skill set in composite failure analysis.”
Fortuitously, Ben’s organisation has just taken ownership of an electron microscope very similar to the one in operation at DSTO Melbourne. “My work and training during this attachment means when I return to DTA I’ll be a relatively experienced user and can pass some of that knowledge on.”
Paul and Ryan agree that this is how international collaborations like TTCP can come to fruition and provide benefits to both countries.